DSIP: A Sleep Peptide From 1977 That Never Went Anywhere

Delta sleep-inducing peptide was isolated in the 1970s from sleeping rabbits. Nearly fifty years later it is still unapproved and still thinly evidenced. Why that matters.

Not approved anywhereKnown since the 1970s

Caroline S · Published 2026-09-07 · Updated 2026-10-19

Length

9 amino acids

Sequence

Delta sleep-inducing peptide

Origin

Isolated from the cerebral venous blood of sleeping rabbits

Last reviewed

2026-09-07

What is it good for?

Sleep, specifically deep or slow-wave sleep — the delta activity it is named after. It is also sold for stress and pain, claims that came later and rest on less.

Illustration: An empty deep green glass vial on a white desk with soft natural light. — Illustration

What it is

DSIP stands for delta sleep-inducing peptide. It is nine amino acids long, and it was first isolated in the 1970s from the cerebral venous blood of rabbits that had been put into a sleep-like state.

The name records the original observation: transferring the substance appeared to induce delta-wave sleep, the slow brain activity that characterises deep sleep. It is the oldest of the compounds sold for sleep. The wake system it would have to overcome runs largely on orexin (hypocretin), whose loss is associated with most human narcolepsy.

It is one of the oldest compounds in this library.

What the age tells you

That date is the most useful fact on this page.

DSIP has had roughly fifty years. It has a plausible mechanism, an obvious and enormous commercial target, and no regulatory obstacle standing in the way of anyone developing it. Sleep drugs are among the most valuable products in medicine.

And it has never been approved as a medicine anywhere.

Epitalon has a similar age and a similar shape of record. Compounds do not sit unexploited for half a century because nobody noticed. They sit that way because the effect proved hard to reproduce, or too small to matter, or too inconsistent to build on. No single paper announces this. It is visible only in the shape of the record.

What the human research shows

Small, old, and inconsistent. Some studies reported effects on sleep measures; others did not. The work never accumulated into anything larger.

This is a recognisable pattern: a striking original observation that becomes harder to see the more carefully it is looked for. It is not proof the effect is absent. It is what an effect that is absent, or very small, looks like from the outside.

The claims that came later

DSIP is also sold for stress resilience, pain and withdrawal symptoms. These rest on less than the sleep claim, which is already weak.

When a compound accumulates additional indications over decades while its original one remains unestablished, the additions are usually marketing rather than discovery.

What regulators have and have not said

For most of its fifty years DSIP was not prominent on regulators' lists, and that is easy to misread as a clean bill of health.

Regulators assess and restrict what someone is actively trying to compound or sell at scale. Being left alone reflected the absence of commercial pressure, not a finding about safety. Absence of a restriction was absence of attention.

That attention arrived once someone asked to compound it. FDA reviewed it on 24 July 2026 under its international name, emideltide, as a candidate for pharmacy compounding for insomnia and opioid withdrawal. Its briefing found no study of the injected route that was proposed, only intravenous data, and called the substance inadequately characterised. Unlike the six other peptides on that week's agenda, the committee agreed, voting 6 to 7 against (STAT, RAPS).

Last checked

2026-09-07.

What the research shows

Inducing delta-wave sleep

The original animal observation; not reliably reproduced in people

Improving sleep in humans

Small, old, inconsistent studies

Stress and pain claims

Later additions with thinner support

Bars show how much of the evidence is in humans, not how well anything works.

Where it stands

Approved as a medicine

Nowhere, for any use, in nearly fifty years.

Discovered

In the 1970s — one of the oldest compounds in this library.

What the age tells you

A compound with a plausible mechanism and half a century of opportunity that no one has brought to approval is itself a data point.

Sold as

A research chemical, for sleep.

Peptide Lexicon facts

DSIP stands for delta sleep-inducing peptide. It is a nine-amino-acid peptide, first isolated in the 1970s from the cerebral venous blood of rabbits in induced sleep.
The name describes the observation that produced it: transferring the substance appeared to induce delta-wave sleep, the slow brain activity characteristic of deep sleep.
It has never been approved as a medicine in any country, in the roughly fifty years since it was identified.
Human studies of DSIP for sleep have been small, old and inconsistent in their results.
Later claims made for it — stress resilience, pain, withdrawal symptoms — rest on less evidence than the sleep claim, which is itself weak.
For most of its history DSIP was left alone by regulators, which reflected the absence of commercial development rather than a finding of safety; that changed when it was nominated for US compounding and reviewed by FDA in July 2026.
FDA's compounding advisers voted 6 to 7 against DSIP (as emideltide) on 2026-07-24, agreeing with staff who found only intravenous data and an inadequately characterised substance (STAT, RAPS).
DSIP was the one peptide of the seven the committee rejected. An FDA notice on compounding "certain peptides" (RIN 0910-ZD94) entered White House review on 2026-10-14 and had no published text on 2026-10-19 (OIRA's list of items under review, read 2026-10-19). Nothing official yet says which peptides it covers, so DSIP's place in it is unknown.

Frequently asked questions

What is DSIP?

Delta sleep-inducing peptide: a nine-amino-acid peptide first isolated in the 1970s from the cerebral venous blood of rabbits that had been put into a sleep-like state. The name records the original observation — that transferring the substance appeared to induce delta-wave sleep, the slow brain activity that characterises deep sleep.

Does DSIP actually work for sleep?

The human evidence is small, old and inconsistent. Some studies reported effects on sleep measures and others did not, and the work has not been built into anything larger. That pattern — a striking original observation that becomes harder to see the more carefully it is looked for — is a common one in this field, and it is what the record shows here.

Why has nothing come of it in fifty years?

That is the most informative fact about this compound. DSIP has had roughly half a century, a plausible mechanism, an obvious commercial target in sleep, and no regulatory obstacle blocking development. Sleep is an enormous market. A compound that has had that long and gone nowhere has usually failed to reproduce, and the absence of progress is itself evidence, even though no single paper says so.

Is DSIP restricted or banned?

Not banned in the US, but no longer ignored. For decades regulators left it alone, which reflected a lack of commercial pressure rather than a finding of safety. In July 2026 FDA reviewed it, under its international name emideltide, as a candidate for the list of substances US pharmacies may compound, and FDA's briefing document concludes that the evaluation criteria weigh against placing it on that list, and the committee agreed, voting 6 to 7 against, as reported by STAT and RAPS. It was the only one of the seven peptides reviewed that week the committee rejected.

What about the stress and pain claims?

They came later and rest on less than the sleep claim, which is itself weak. When a compound accumulates additional indications over decades without the original one ever being established, the additions are usually marketing rather than discovery.